Pocket-transit.



Mmm BESTAVAILABLE COF Emma MH 16,1905.

W. D. VBRSGHQYLB.

POCKET'TRAN-SIT.

APPLIOATIO YILED D20. 2, 1514..

2 SHZETHHEBT 1.

TTORNEYS 51:# er M BEST AVMLABLE @Op No. 790.153. PATBNTIBD MAY 1e,1905. W'. D. VEaSCHGYLB.

POCKET RANSIT.

APPLICATIOE FILED DEO. 2, 1904.

2 SHEETS-funn z.

ATTORNEYS UNITED STATES BST AVAILABLE COP Patented May 16, 1905.

VI'LLIANI D. VERSCHOYLE, OF SEATTLE, WASHINGTON.

POCKET-TRANSIT.

SPECIFICATION forming part of Letters Patent No. 790,163, dated May 16,1905.

Application filed December 2, 1904. Serial No. 235,197.

To all: whom '/fl 71mg/ concern:

Be it known that l, VrLLrAu DaNi-IAM Venscnovnn, a citizen of the UnitedStates, residing at Seattle, in the county ot' King and State ofill/yashington, have invented a new and useful Improvement inPocket-Transits, of which the following is a specification.

My invention is in the nature of a pockettransitfor the use ofprospectors, miners, surveyors, mariners, and others, whereby thehorizontal magnetic bearing (or angle which lies horizontally betweenthe magnetic meridian and the line intersecting the eye of the observerand any distant object) maybe quickly ascertained and whereby also maybe ascertained the vertical angle lying vertically between thc linejoining the horizon to the observers eye and the line intersecting theobservers eye from a point above or below the horizon, both of saidhorizontal and vertical angles being observed and read at once in oneoperation and with great accuracy.

My invention consists in the novel construction and arrangement of theparts of the instrument, which I will now proceed to describe withreference to the drawings, in which- Figure 1 is a plan view of theentire instrumen t. Fig. 2 is an ed ge view of the same looking in thedirection of the arrow in Fig. 1. Fig. 3 is a vertical central sectionon line 3 3 of Fig. 1. Fig. 4 is an outside face view of thes\\ivelplate. Fig. Llis a vertical section of the same on liueyl. Fig.4" is a rear or inside view of the swivel-plate, and Fig. 4 is ahorizontal section otl the saine on line 4c Llc. Fig. 5 is a sectionalview through the case, showing a friction-brake for holding the mag'-netic needle fixed; and Fig. 5 is a partial top View of the same. Fig. 6is a view looking through the hollow swivel-plate. Fig. 7 is a top viewof the sight-arm. Fig. T" is a face view of the folding end wing withcross-lines. Fig. 7" isa face View of the middle part of the arm. Fig. Tis a side view, and Fig. 7" an end view, of the swivel end of thesight-arm; and Fig. '7 shows details of an inclosing yoke for holdingthesight-arm on the swivel-plate. Fig. S is a top view of a graduated platebearing the magiieticneedle. Fig Qshows details of a rellccting-prismand its holder, and Fig.

10 is a perspective view of the face of the prism.

In the drawings, A is the compass-box, which has a detachable coverprovided near one edge with 'a glass lens A3 for focusing the light on acertain point below. Below the detachable cover is a glass face A4,retained by a marginal metal ring A. This glass face and retaining ringmay, however, be dispensed with.

B, Figs. 4 to 4, is asWivel-plate secured to the edge of the box, asinFig. 1, and forminga pivot or swiveling center upon which the sightarniC C turns in a vertical plane. This swivel-plate is curved onone side tofit the circle of the box and its outer face lies in a tangential plane.A central hole I, having a flanged and undercut collar, is formed in theswivel-plate, and this hole forms a window through which the readings ona scale within the box may be observed. The swivel-plate is secured tothe box by screws through screwholes B', and on the upper side of theswivelplate is constructed a semicircular scale-plate B2, graduated inangular degrees in a vertical plane from zero at the top to ninetydegrees at each end, as seen in Fig. 4.

C C C2designatea hinged and folding sightarm. TheinnerportionCswivelsontheswivelplate B. The middle portion C' is jointed to C and has a holeit near its middle, and the outer section or wing C? has afoldingknucklejoint, so that it stands at right angles to the arm C C', as inFig. 7, or may be folded inwardly. This. wing is a hollow frame withcross wires or hairs, as seen in Fig. 7". The inner section C of the armhas a central hole through it, with a square recess c2 on the outerface. The central hole coincides with the opening I in the swivel-plate,and the square recess c2 receives a glass prism D', which is retained bya metal hood D, as seen in Figs. 1, Q, and 9. This prism formsareiiector designed to turn a beam of light ninety degrees. The hubportion of arm C is undercut internally to lit and 'be retained upon theundercut flange of the swivel-plate B, forming a journal, and the hub isheld on the swivelplate Iiournal by means of a detachable yoke y, Figs.2 and 7b'.

F (see Figs. 3 and 8) is a metal disk having a beveled and dependentedge F, on which beveled edge is a graduated and figured scalerepresenting all the points of the compass, the figures and lettersbeing inverted (to make the reflection of them upright) and allpoints,with their usually-accepted representative numerals, being movedaround in relation to the magnetic needle ninety degrees in a directionsimilar to the travel of the hands of a clock. The disk F is attached toand moved by a subjacent magnet F by means of a hub F2, having apivot-jewel F3, mounted upon the pivot-pin F5, so that the disk andmagnet are free to rotate together, as seen in Fig. 3. To hold the diskand magnet stationary, a-frictionbrake is provided, as seen in Figs. 3,5, and 5. A rectangular springframe G has at the top twoinwardly-projecting arms arranged diametrically and terminating in loopsG2 G2, which embrace the Vhub F2 of the graduated disk. The expansivetendency of the spring-frame causes the loops G2 to bind and hold thehub F2; but when the disk and magnet are to be released, so as to allowthe magnet to adjust itself in exercising its normal functions, thespringframe G is compressed, so as to slide the upper arms inwardlytoward each other. To do this, pins G' Gr (seeFig. 5) are formed on theends of the spring-frame and are allowed to project through holes in thebox or casing, so that the pins may be pressed inwardly by the thumb andforeiinger.

J is a small spirit-level arranged parallel to the right arm in the sideof the box A, as seen in Figs. 3 and 6. This spirit-level is retained inplace by the swivel-plate B, and the bubble is visible through theorilice I. A hair or wire J Fig.'6, or a mark on the glass shows whensaid bubble is under the central point of the opening I and the compassis level.

H, Figs. l and 2, is a pointer attached by screws to the top of themovable sight-arm C and is adapted to traverse the stationary scale B2on the swivel-plate. This pointer may have a Vernier, if desired.

The operation of my transit isas follows: The box A is held horizon taland level, and the eye is sighted along the line m in Fig. l to bringthe edge oi' prism DQ Fig. 2.' and the cross-lines in wing C2 intoalinement with the remote object. Light concentrated by lens A3illumines the edge of the scale Fi immediately opposite the opening I,and the reflection of this reading is by the prism thrown backward atninety degrees and is visible to the eye at rc, giving the magneticbearing in a horizontal plane-that is to say, the magnetic bearing ofthe line from a' to the distant object will berepresented by-the figuresappearing in the face of the prism, since this line is parallel to thatdiameter of the circle which BEST AVAILABLE COP" J will be also visiblein the face of the prism,

and when it is under the central mark provided zero on the scale B2 willbe at right angles to a horizontal line and the compass will be level,and when the axis of the sightarm C is raised or depressed the anglethrough which it is rotated is shown in two ways-'ii rst, on scale B2 bythe pointer H, and, secondly, by reflection through the prism. Thisvertical angle when read by reflection through the prism utilizes thehair-line J of Fig. 6 in connection with a scale shown in Fig. 10, inwhich K is a graduated semicircular metal scale of angular degreesfigured from zero at the top to ninety degrees at 'each end and which isattached over the face of the prism. When the sight-arm C is turnedthrough the vertical plane, the reiiection of wire J is turned through acorresponding angle, which is observed on the scale K. This makes itpossible to observe and read off the horizontal and vertical angles of apoint at the same time through the prism; but where great accuracy isrequired the reading of the scale B2 and pointer H With Vernier may bemade available.

When the instrument is to be folded for the pocket, the wing C2 and partC are folded as in dotted lines in Fig. 1, the opening 71, in the part Cfalling over and surrounding the prism and serving in a measure toprotect the same.

The face of the prism is 'preferably made convex, as in Figs. 1 and 9,to magnify the readings. l

In my invention it will be seen that as soon as the bubble of thespirit-level comes to rest .at the center mark and the needle is at restin the magnetic meridian and the front crosswires intersect the objectto be observed the work of obtaining both the horizontal and thevertical angles has been completed. This generally requires twoinstruments-say, a prismatic compass and an Abney level-or if oneinstrument, such as the Brunton pockettransit, is used it must be set uptwice in two different positions, thus taking twice the time andlessening the accuracy, owing to the improbability of the coincidence ofthe two lines observed.

Having thus described my invention, what T claim as new, and desire tosecure by Letters Patent, is-

1. A transit instrument, comprising a compass having its magnetic needleattached to and movable with a circular scale, combined with a case anda reflector at the side of the compass to expose the reading ot' thecompass in the direction of the line of sighting substantially asdescribed.

2. A transit instrument, comprising a compass having its magnetic needleattached to and movable with a circular scale, combined with a casehaving a window at its side, a reiiecting-prism located at this windowand a sighting-arm substantially as described.

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3. A transit instrument, comprising acompass with atangentially-arranged sightingarm attached directly to the side of thecompass and a reflector at the point of junction of the sighting-arm andcompass substantially as described.

4. A transit instrument, comprisinga case, a magnetic needle, anattached disk with beveled edge bearing the compass-scale, atangentially-arranged sighting-arrn and a reflector located at thejunction of said arm with the case substantially as described.

5. A transit instrument, comprising a case with a hole in its side, amagnetic needle, an attached com pass-scale, a light-concentrating lenslocated above the opening in the case, a tangentially-arrangedsighting-arm, and a relector located at the junction of the said armwith the case substantially as described.

6. A transit instrument, comprising a case with a hole in its side, anda vertical hair-line across the hole, a magnetic needle, an attachedcompass-scale, a tangentially-arranged sighting-arm, a reflectorarranged at the junction ot' said arm with the case, and a spirit-levellocated between the compass-scale and the reiector substantially asdescribed.

7. A transit instrument, comprising a com? pass, a tangentiallyarrangedsighting-arm having an opening through it at its point of junction withthe compass, and a reflector adjusted in front of said opening toreflect at an angle of ninety degrees substantially as and l'or thepurpose described.

8. A transit instrument, comprising a compass, a tangential sighting-armarrangedl to swing in a vertical plane, a reflector adjusted at thepoint of junction between the compass and sighting-arm, and means fornoting at one observation both the horizontal angle of thecompass-readings and the vertical angle of the elevation or depressionsubstantially as described. 4

9. A transit instrument, comprising a compass, a tangential sighting-armarranged to swing in a vertical plane, a reflector located at thejunction of the arm and compass, a spiritlevel with vertical hair-linelocated between the compass and the reflector and a circular scalearranged on the observers side of the refiector substantially as and forthe purpose described.

10. Atransit instrument, comprising a case, a magnetic needle withattached compass-scale having a projecting hub and a friction-brakebearing on said hub substantially as described.

1 l. A transit instrument, comprising a case, a magnetic needle withattached compass-scale having a projecting hub, and tyvo perforatedspring-arms embracing the hub and having external connections for manualcompression to release the frictional contact with the hub substantiallyas described.

WILLIAM D. VERSCHOYLE.

Witnesses:

BURTON E. BENNETT, RAY MCKAY.

